Pneumatic piano-player.



. C. E. PETERSON.

A PNEUMATIC PIANO PLAYER.

APPLICATION FILED IUNEZI. 1917.

1,274,766. Patente-Mug. 6,1918.

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CLAUS E. PETERSON, 0E WORCESTER, MASSACHUSETTS, ASSIGNCE, :BY MESNEASSIGN- MENTS, To IvEESoN PIANO PLAYER COMPANY, oE'BoSToN,MASSACHUSETTS, A Con- PoEATIoNoE MASSACHUSETTS.

PNEUMATIC PIANO-PLAYER.

Specification of Letters Patent. Patented A110'. 6, 1918.

Application mea June 21, 1917. Serial No. 176,216.

Toallwwm it may concern:

Be it known'that` I, CLAUS E. PETERSON, a citizen of the United States,residing at lvorcester, in the county of Vorcester and Commonwealth ofMassachusetts, have invented a new and useful Improvement in PneumaticPiano-Players, of which the tollowing is a specification, accompanied bydrawings forming a part of the same.

My present invention relates to so called bleed devices of a pianoplayer and to an improved connection between the bleed device and theprimary valve, which may be readily applied, and in which the use ofrubber tubing Vmay be avoided. In the accompanying drawings I have shownso much of a pneumatic piano player as'will be necessary to illustratethe character of my present invention.

The piano player embodying my present invention is similar to thosenowin com-y mon use, and comprises a motor pneumatic, a Secondary valvefor controlling the action of the motor pneumatic, and a primary valvewhose action controlled by the passage of a perforated sheet over thetracker bar. In the accompanying drawings,

Figure 1 represents a rear view of a portion of the player action. l

Fig. 2 is a sectional view on the plane of the broken line 2 2, Fig. 1,showing the arrangement of the motor pneumatic vand the secondary andprimary valves. Other por-` tions of the player mechanism not concern edin my present invention, and therefore not shown, will be wellunderstood by those conversant with this class of instruments.

Fig. 3 is a detached view of the connection between the hollow bleed barand the primary valve.

Like reference characters refer to like parts in the different figures.

My improved player action comprises, in the present instance, three bars1, 2 and 3, extending lengthwise the instrument, preferably made ofwood, and having attached to their upper surfaces Steel plates 4, 5 and6. The upper bar 1 is shown in transverse sectional view in Fig. 2, towhich reference is particularly made to illuStrat-ethe character of mypresent invention. rlhe wooden bar 1 is provided with longitudinalchannels 7 and 8, the former forming the wind chest 'for the primaryvalve, and the latter the wind chest for the secondary valve, said Windchests being suitably connected at their .ends bv pipes 9 and 10 with anair exhausting mechanism, not Shown, such as a bellows or the like. .ARecessed below the wind chest 7 and spaced apart according tothedistance between the keys of thepiano are air chambers 11, one of whichvis Shown in Fig. 2. The chamber 11 is Separated from the wind chest 7by a yielding diaphragm 12 provided at its `center with a 'washer 13upon which the lower end of the primary valve stem 14 rests. Mountedupon the steel plate 4 is van vinverted cup'v 15, having an opening 16communicating with the wind chest 7, and an opening117 leading to theouter air. Y f

Thevalve stem 14 is provided with the packed-valves 18 and 19. AS thevalve stem 141s raised the valve 18 contacts with the steel plate 4 andcloses the opening 16, and the same movement ofthe valve stem 14 raisesthe valve 19 to allow atmospheric air to flow through the opening 17into the inverted cup 15 and through the tubular pas- Sage 20 to an airchamber 21, shown by broken lines in Fig. 2, and byits pressure to raisethe `diaphragm 22. The lifting of the diaphragm 22'raises al secondaryvalve, not shown, which cuts olf the motor bellows V22a from theoutsidev airand connects it with the wind chest 8, in the usual and wellknown manner. The air chamber 11 of the primary valve is connected bypipes 23 and 24 with theV perforations of the tracker bar, and wheneverthese perforations are uncovered by the perforations of the music sheet,air at atmospheric pressure will How through the pipes 23 and 24 to liftthe diaphragm 12. As soon as the perforation in the tracker bar isclosed by the music Sheet, the pressure of air in the chamber 11 beginsto be reduced by a small bleed opening 25 in the pipe 24, said bleedopening, opening into a closed tubular bar 26. The tubular bar 26 isconnected with an air exhaust mechanism, not shown, by means of a pipe27, Fig. 2, by which a partial vacuum is maintained in the tubular bar26. Upon the upper Side of the bar 26 are holes placed opposite thebleed openings 25 and closed by screws 28, which can be removed to allowaccess to the bleed openings in case the pas'- sage through the latterbecomes impeded by dust or other foreignV substances.

The pipe 23 is bent at right angles at its lower end and inserted in thewooden block l in alinement with a passageway leading to the chamber 11,and its upper end is soldered into a cup shaped cap 29 having a flange3Q, whichis notched on opposite sides' at 31, 3l, to receive attachingscrews 32 by which the flanged caps are secured tothe bar 26. The cap 29covers the end of the pipe 24, allowing the removal of dust from thepipes 24 and 23 by the removal of the cap 29, and the removal of a screw28 over a bleed hole 25 allows the latter yto be cleared of dust, or tobe enlarged, if required, in order to increase the bleeding action.`

The bars containing` longitudinal charnbers forming wind kchests and thearrangement of pneumatically operated valves for controlling the actionof the motor bellows form no part of my presentl invention, as thisportion of the within described apparatus is substantially the same asthe pneumatic apparatus now in use in piano players. Neither do I claimbroadly the employment of a tubular bar inclosing a vent chamber havinga bleed device located between the openings of a' tracker bar and theprimary valve mechanism, as such has been hitherto proposed. Accordingto my present invention, I place the tubular bar 26 directly over thefront side of the Vbars l, and I lead pipes 2,4 horizontally from atracker bar through the tubular bar 26, from the backside, leavingthetop and front sides, which are readily accessible, for the removal' ofthe screws 28 and the flanged caps 29. The horizontal pipe 24. extendsthrough the tubular bar 26 and terminates in the detachable cap 29, its

only connection with theinterior of the tubular bar being through thebleed opening 25.

The bleed device of a pneumatically actuated piano is a delicatemechanism, owing to the minuteness of the opening and the operation ofthe instrument depends for sensitiveness and responsiveness inmaintaining the size of the bleed openings uniform. By my arrangement ofthe, bleed mechanism, the openings 25 are readily accessible by neans ofthe screws 28 which are located upon the top side of the tubular bar,and the ends of the pipes 25 are accessible by the removal of the caps29. The pipes 23 are soldered to the caps 29 and are readily inserted inthe block l, and the caps 29 are detachably attached tothe tubular bar26 by screws 32.

I claim:

In an instrument of the character described, comprising a series of barshaving valve controlled wind chests and motor bellows communicatingtherewith forming a pneumatic mechanism, the combination with saidpneumatic mechanism of a tubular bar inclosing anexhaust chamber, andsupported directly over the rear edge of said bars, pipes leading fromtracker bar and passing through said tubular bar from the rear to thefront side Vand provided with a bleed opening upon their upper sides,screws held in the upper side of said tubular bar opposite saidopenings, caps detachably attached to the front side of said tubularbar, and pipespermanently attached to said caps and leading from saidcaps to theprimary valves of the instrument. p

CLAUS E. PETERSON. Witnesses:

NELLIE WHALEN, PENnLorn CoMBnRBAoK.

Copies of this patent may be obtained for ive cents each, 'liyladdressing` the Commissioner of Patents, Washington, D. C.

